Merge branch 'development'

Limit the maximum number of open file handles in Docker images.
Increase the level of optimisation (to -O3) while building the Shairport Sync application itself.
Enabled termination of a disconnected session in AirPlay 2 operation after a timeout, which was disabled by default.
Fixed a bug that prevented Shairport Sync from terminating cleanly when a fatal error that occurred while directly accessing the alsa output device.
Fixed a bug that prevented Shairport Sync from recovering cleanly if a player disconnected without warning. The problem was that the player thread would not respond to cancel request. Fixed by moving a pthreadtestcancel() call to the innermost loop.
Fixed compilation errors on old versions of Mac OS X by, reordering some of the files to be included in shairport.c.
Avoided using TCP_KEEPINTVL and TCP_KEEPCNT if they are not defined (they are not defined in older versions of Mac OS X).
Fixed a race condition with the metadata queues. The problem was that the queues were being initialised by threads launched by the main thread which, having started the threads, proceeded to use the queues. But if the threads were late in starting, the queues might not be initialised by the time the main thread tried to use them. Fixed by initialising the queues in the main thread.
Enable the ALSA backend to access mixers on a devices with a hdmi: prefix.
Update the help text for the ALSA backend to denote HDMI devices using the hdmi: prefix rather than hw:.
Manage thread cancellation state explicitly in audio_ao.c
CAR INSTALL guide: Simplify some of the wording. Change order and allow a few seconds before starting systemd-timesync service.

CAR INSTALL.md

@@ -191,40 +191,45 @@ if test $MODE = RUN ; then
 else
 
  # If script execution gets in here, it starts services needed for normal operation.
- /bin/systemctl start systemd-timesyncd || :
  /bin/systemctl start dhcpcd || /bin/systemctl start NetworkManager || :
+ /bin/sleep 2 # may be necessary while the network becomes available
+ /bin/systemctl start systemd-timesyncd || :
 
 fi
 
 exit 0 # normal exit here
 ```
 
-#### Disable Unused Services
+#### Disable Unused Services - Optional
 These optional steps have been tested on a Raspberry Pi only -- they have not been tested on other systems.
 Some services are not necessary for this setup and can be disabled as follows:
 ```
 # systemctl disable keyboard-setup
 # systemctl disable triggerhappy
 # systemctl disable dphys-swapfile
 ```
-#### Optional: Read-only mode – Raspberry Pi Specific
-This optional step is applicable to a Raspberry Pi only. Run `sudo raspi-config` and then choose `Performance Options` > `Overlay Filesystem` and choose to enable the overlay filesystem, and to set the boot partition to be write-protected. (The idea here is that this offers more protection against files being corrupted by the sudden removal of power.)
 
-### Final Steps
 
+#### Disable Unused Services - Mandatory
 You now need to disable some services; that is, you need to stop them starting automatically on power-up. This is because they either interfere with the system's operation in WiFi Access Point mode, or because they won't work when the system isn't connected to the Internet. Only one of the `NetworkManager` and the `dhcpcd` service will be present in your system, but it's no harm to try to disable both.
 ```
 # systemctl disable dhcpcd
 # systemctl disable NetworkManager
 # systemctl disable wpa_supplicant
 # systemctl disable systemd-timesyncd
 ```
-Lastly, note that the WiFi credentials you used initially to connect to your network (e.g. your home network) will have been stored in the system in plain text. This is convenient for when you want to reconnect to update (see later), but if you prefer to delete them, they will be in `/etc/wpa_supplicant/wpa_supplicant.conf`
+Lastly, note that the WiFi credentials you used initially to connect to your network (e.g. your home network) will have been stored in the system in plain text. This is convenient for when you want to reconnect to update (see later), but if you prefer to delete them, they will be in `/etc/wpa_supplicant/wpa_supplicant.conf`.
 
+#### Optional: Read-only mode – Raspberry Pi Specific
+This optional step is applicable to a Raspberry Pi only. Run `sudo raspi-config` and then choose `Performance Options` > `Overlay Filesystem` and choose to enable the overlay filesystem, and to set the boot partition to be write-protected. (The idea here is that this offers more protection against files being corrupted by the sudden removal of power.)
+
+### Final Step
 When you are finished, carefully power down the machine before unplugging it from power:
 ```
 # poweroff
 ```
+Note: doing a `reboot` here doesn't seem to work properly -- it really does seem necessary to power off.
+
 ### Ready
 Install the Raspberry Pi in your car. It should be powered from a source that is switched off when you leave the car, otherwise the slight current drain will eventually flatten the car's battery.
 
@@ -241,7 +246,7 @@ However, if you're *upgrading* the operating system to e.g. from Bullseye to Boo
 If it's a Raspberry Pi and you have optionally enabled the read-only mode, you must take the device out of Read-only mode: 
 Run `sudo raspi-config` and then choose `Performance Options` > `Overlay Filesystem` and choose to disable the overlay filesystem and to set the boot partition not to be write-protected. This is so that changes can be written to the file system; you can make the filesystem read-only again later. Save the changes and reboot the system.
 #### Undo Optimisations
-If you have disabled any of the services listed in the [Disable Unused Services](#disable-unused-services) section, you should re-enable them. (But *do not* re-eneable `NetworkManager`, `dhcpcd`, `wpa_supplicant` or `systemd-timesyncd` -- they are handled specially by the startup script.)
+If you have disabled any of the services listed in the [Disable Unused Services - Optional](#disable-unused-services---optional) section, you should re-enable them. (But *do not* re-eneable `NetworkManager`, `dhcpcd`, `wpa_supplicant` or `systemd-timesyncd` -- they are handled specially by the startup script.)
 #### Perform Legacy Updates
 Over time, the arrangements by which the system is prepared for operation has changed to make it easier to revert to normal operation when necessary for maintenance, updates, etc. A small number of the old settings need to be changed to bring them up to date with the present arrangements. Once the required changes have been made, your system will be ready for the update process detailed below. Here are those legacy changes you need to make, just once:
 

audio_alsa.c

@@ -1,7 +1,7 @@
 /*
  * libalsa output driver. This file is part of Shairport.
  * Copyright (c) Muffinman, Skaman 2013
- * Copyright (c) Mike Brady 2014 -- 2022
+ * Copyright (c) Mike Brady 2014 -- 2024
  * All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person
@@ -146,6 +146,7 @@ long alsa_mix_minv, alsa_mix_maxv;
 long alsa_mix_mindb, alsa_mix_maxdb;
 
 char *alsa_out_dev = "default";
+char *hw_alsa_out_dev = NULL;
 char *alsa_mix_dev = NULL;
 char *alsa_mix_ctrl = NULL;
 int alsa_mix_index = 0;
@@ -279,19 +280,78 @@ uint64_t frames_sent_for_playing;
 // frames_sent_for_playing (which Shairport Sync might hold) would be invalid.
 int frames_sent_break_occurred;
 
+// if a device name ends in ",DEV=0", drop it. Then if it also begins with "CARD=", drop that too.
+static void simplify_and_printf_mutable_device_name(char *device_name) {
+ if (strstr(device_name, ",DEV=0") == device_name + strlen(device_name) - strlen(",DEV=0")) {
+ char *shortened_device_name = str_replace(device_name, ",DEV=0", "");
+ char *simplified_device_name = str_replace(shortened_device_name, "CARD=", "");
+ printf(" \"%s\"\n", simplified_device_name);
+ free(simplified_device_name);
+ free(shortened_device_name);
+ } else {
+ printf(" \"%s\"\n", device_name);
+ }
+}
+
 static void help(void) {
+
  printf(" -d output-device set the output device, default is \"default\".\n"
  " -c mixer-control set the mixer control name, default is to use no mixer.\n"
  " -m mixer-device set the mixer device, default is the output device.\n"
  " -i mixer-index set the mixer index, default is 0.\n");
- int r = system("if [ -d /proc/asound ] ; then echo \" hardware output devices:\" ; ls -al "
- "/proc/asound/ 2>/dev/null | grep '\\->' | tr -s ' ' | cut -d ' ' -f 9 | while "
- "read line; do echo \" \\\"hw:$line\\\"\" ; done ; fi");
- if (r != 0)
- debug(2, "error %d executing a script to list alsa hardware device names", r);
+ // look for devices with a name prefix of hw: or hdmi:
+ int card_number = -1;
+ snd_card_next(&card_number);
+
+ if (card_number < 0) {
+ printf(" no hardware output devices found.\n");
+ }
+
+ int at_least_one_device_found = 0;
+ while (card_number >= 0) {
+ void **hints;
+ char *hdmi_str = NULL;
+ char *hw_str = NULL;
+ if (snd_device_name_hint(card_number, "pcm", &hints) == 0) {
+ void **device_on_card_hints = hints;
+ while (*device_on_card_hints != NULL) {
+ char *device_on_card_name = snd_device_name_get_hint(*device_on_card_hints, "NAME");
+ if ((strstr(device_on_card_name, "hw:") == device_on_card_name) && (hw_str == NULL))
+ hw_str = strdup(device_on_card_name);
+ if ((strstr(device_on_card_name, "hdmi:") == device_on_card_name) && (hdmi_str == NULL))
+ hdmi_str = strdup(device_on_card_name);
+ free(device_on_card_name);
+ device_on_card_hints++;
+ }
+ snd_device_name_free_hint(hints);
+ if ((hdmi_str != NULL) || (hw_str != NULL)) {
+ if (at_least_one_device_found == 0) {
+ printf(" hardware output devices:\n");
+ at_least_one_device_found = 1;
+ }
+ }
+ if (hdmi_str != NULL) {
+ simplify_and_printf_mutable_device_name(hdmi_str);
+ } else if (hw_str != NULL) {
+ simplify_and_printf_mutable_device_name(hw_str);
+ }
+ if (hdmi_str != NULL)
+ free(hdmi_str);
+ if (hw_str != NULL)
+ free(hw_str);
+ }
+ snd_card_next(&card_number);
+ }
+ if (at_least_one_device_found == 0)
+ printf(" no hardware output devices found.\n");
 }
 
-void set_alsa_out_dev(char *dev) { alsa_out_dev = dev; } // ugh -- not static!
+void set_alsa_out_dev(char *dev) {
+ alsa_out_dev = dev;
+ if (hw_alsa_out_dev != NULL)
+ free(hw_alsa_out_dev);
+ hw_alsa_out_dev = str_replace(alsa_out_dev, "hdmi:", "hw:");
+} // ugh -- not static!
 
 // assuming pthread cancellation is disabled
 // returns zero of all is okay, a Unx error code if there's a problem
@@ -902,7 +962,7 @@ static int prepare_mixer() {
  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
 
  if (alsa_mix_dev == NULL)
- alsa_mix_dev = alsa_out_dev;
+ alsa_mix_dev = hw_alsa_out_dev;
 
  // Now, start trying to initialise the alsa device with the settings
  // obtained
@@ -1355,11 +1415,19 @@ static int init(int argc, char **argv) {
  }
 
  debug(1, "alsa: output device name is \"%s\".", alsa_out_dev);
-
+
+
+ // now, we need a version of the alsa_out_dev that substitutes "hw:" for "hdmi" if it's
+ // there. It seems hw:1 would be a valid devcie name where hdmi:1 would not
+
+ if (alsa_out_dev != NULL)
+ hw_alsa_out_dev = str_replace(alsa_out_dev, "hdmi:", "hw:");
+
  // so, now, if the option to keep the DAC running has been selected, start a
  // thread to monitor the
  // length of the queue
  // if the queue gets too short, stuff it with silence
+
 
  pthread_create(&alsa_buffer_monitor_thread, NULL, &alsa_buffer_monitor_thread_code, NULL);
 
@@ -1376,6 +1444,8 @@ static void deinit(void) {
  debug(3, "Join buffer monitor thread.");
  pthread_join(alsa_buffer_monitor_thread, NULL);
  pthread_setcancelstate(oldState, NULL);
+ if (hw_alsa_out_dev != NULL)
+ free(hw_alsa_out_dev);
 }
 
 static int set_mute_state() {

audio_ao.c

@@ -69,6 +69,8 @@ static void help(void) {
 }
 
 static int init(int argc, char **argv) {
+ int oldState;
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
  ao_initialize();
  driver = ao_default_driver_id();
  if (driver == -1) {
@@ -133,14 +135,18 @@ static int init(int argc, char **argv) {
  fmt.byte_format = AO_FMT_NATIVE;
  fmt.matrix = strdup("L,R");
  }
+ pthread_setcancelstate(oldState, NULL);
  return 0;
 }
 
 static void deinit(void) {
+ int oldState;
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
  if (dev != NULL)
  ao_close(dev);
  dev = NULL;
  ao_shutdown();
+ pthread_setcancelstate(oldState, NULL);
 }
 
 static void start(__attribute__((unused)) int sample_rate,
@@ -166,10 +172,13 @@ static int play(void *buf, int samples, __attribute__((unused)) int sample_type,
 
 static void stop(void) {
  // debug(1,"libao stop");
+ int oldState;
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
  if (dev != NULL) {
  ao_close(dev);
  dev = NULL;
  }
+ pthread_setcancelstate(oldState, NULL);
 }
 
 audio_output audio_ao = {.name = "ao",

configure.ac

@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.50])
-AC_INIT([shairport-sync], [4.3.3], [[email protected]])
+AC_INIT([shairport-sync], [4.3.4], [[email protected]])
 AM_INIT_AUTOMAKE([subdir-objects])
 AC_CONFIG_SRCDIR([shairport.c])
 AC_CONFIG_HEADERS([config.h])

docker/Dockerfile

@@ -55,7 +55,7 @@ COPY . .
 RUN git checkout "$SHAIRPORT_SYNC_BRANCH"
 WORKDIR /shairport-sync/build
 RUN autoreconf -i ../
-RUN ../configure --sysconfdir=/etc --with-alsa --with-pa --with-soxr --with-avahi --with-ssl=openssl \
+RUN CFLAGS="-O3" CXXFLAGS="-O3" ../configure --sysconfdir=/etc --with-alsa --with-pa --with-soxr --with-avahi --with-ssl=openssl \
  --with-airplay-2 --with-metadata --with-dummy --with-pipe --with-dbus-interface \
  --with-stdout --with-mpris-interface --with-mqtt-client \
  --with-apple-alac --with-convolution

docker/classic/Dockerfile

@@ -40,7 +40,7 @@ COPY . .
 RUN git checkout "$SHAIRPORT_SYNC_BRANCH"
 WORKDIR /shairport-sync/build
 RUN autoreconf -i ../
-RUN ../configure --sysconfdir=/etc --with-alsa --with-pa --with-soxr --with-avahi --with-ssl=mbedtls \
+RUN CFLAGS="-O3" CXXFLAGS="-O3" ../configure --sysconfdir=/etc --with-alsa --with-pa --with-soxr --with-avahi --with-ssl=mbedtls \
  --with-metadata --with-dummy --with-pipe --with-dbus-interface \
  --with-stdout --with-mpris-interface --with-mqtt-client \
  --with-apple-alac --with-convolution

docker/classic/etc/s6-overlay/s6-rc.d/02-dbus/run

@@ -1,3 +1,7 @@
 #!/command/with-contenv sh
+
+# Set the limit to the same value Docker has been using in earlier version.
+ulimit -n 1048576
+
 echo "Starting dbus"
 exec s6-notifyoncheck dbus-daemon --system --nofork --nopidfile

docker/etc/s6-overlay/s6-rc.d/02-dbus/run

@@ -1,3 +1,7 @@
 #!/command/with-contenv sh
+
+# Set the limit to the same value Docker has been using in earlier version.
+ulimit -n 1048576
+
 echo "Starting dbus"
 exec s6-notifyoncheck dbus-daemon --system --nofork --nopidfile

player.c

@@ -921,7 +921,7 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn) {
  pthread_cleanup_push(buffer_get_frame_cleanup_handler,
  (void *)conn); // undo what's been done so far
  do {
-
+ pthread_testcancel(); // even if no packets are coming in...
  // get the time
  local_time_now = get_absolute_time_in_ns(); // type okay
  // debug(3, "buffer_get_frame is iterating");
@@ -2269,9 +2269,7 @@ void *player_thread_func(void *arg) {
  if (conn->input_bytes_per_frame == 0)
  debug(1, "conn->input_bytes_per_frame is zero!");
 
- pthread_testcancel(); // allow a pthread_cancel request to take effect.
- abuf_t *inframe = buffer_get_frame(conn); // this has cancellation point(s), but it's not
- // guaranteed that they'll always be executed
+ abuf_t *inframe = buffer_get_frame(conn); // this has a (needed!) deliberate cancellation point in it.
  uint64_t local_time_now = get_absolute_time_in_ns(); // types okay
  config.last_access_to_volume_info_time =
  local_time_now; // ensure volume info remains seen as valid
@@ -3233,14 +3231,6 @@ void *player_thread_func(void *arg) {
  frames_seen_in_this_logging_interval = 0;
  }
 
- // update the watchdog
- if ((config.dont_check_timeout == 0) && (config.timeout != 0)) {
- uint64_t time_now = get_absolute_time_in_ns();
- debug_mutex_lock(&conn->watchdog_mutex, 1000, 0);
- conn->watchdog_bark_time = time_now;
- debug_mutex_unlock(&conn->watchdog_mutex, 0);
- }
-
  // debug(1,"Sync error %lld frames. Amount to stuff %d." ,sync_error,amount_to_stuff);
 
  // new stats calculation. We want a running average of sync error, drift, adjustment,

player.h

@@ -167,14 +167,11 @@ typedef struct {
  SOCKADDR remote, local;
  volatile int stop;
  volatile int running;
- volatile uint64_t watchdog_bark_time;
- volatile int watchdog_barks; // number of times the watchdog has timed out and done something
 
  uint64_t playstart;
  uint64_t connection_start_time; // the time the device is selected, which could be a long time
  // before a play
- pthread_t thread, timer_requester, rtp_audio_thread, rtp_control_thread, rtp_timing_thread,
- player_watchdog_thread;
+ pthread_t thread, timer_requester, rtp_audio_thread, rtp_control_thread, rtp_timing_thread;
 
  // buffers to delete on exit
  int32_t *tbuf;
@@ -380,7 +377,6 @@ typedef struct {
  // request in flight at the same time
 
  pthread_mutex_t reference_time_mutex;
- pthread_mutex_t watchdog_mutex;
 
  double local_to_remote_time_gradient; // if no drift, this would be exactly 1.0; likely it's
  // slightly above or below.